/*
* This program is free software; you can redistribute it and/or modify it under the
* terms of the GNU Lesser General Public License, version 2.1 as published by the Free Software
* Foundation.
*
* You should have received a copy of the GNU Lesser General Public License along with this
* program; if not, you can obtain a copy at http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html
* or from the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
* This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
* without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU Lesser General Public License for more details.
*
* Copyright (c) 2001 - 2013 Object Refinery Ltd, Pentaho Corporation and Contributors.. All rights reserved.
*/
package org.pentaho.reporting.engine.classic.core.function;
import java.math.BigDecimal;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.pentaho.reporting.engine.classic.core.event.ReportEvent;
import org.pentaho.reporting.engine.classic.core.util.Sequence;
/**
* A report function that calculates the average of one field (column) from the TableModel. This function produces a
* running total, no global total. The function can be used in two ways: <ul> <li>to calculate an average value for the
* entire report;</li> <li>to calculate an average value within a particular group;</li> </ul> This function expects its
* input values to be either java.lang.Number instances or Strings that can be parsed to java.lang.Number instances
* using a java.text.DecimalFormat.
* <p/>
* The function understands two parameters, the <code>field</code> parameter is required and denotes the name of an
* ItemBand-field which gets summed up.
* <p/>
* The parameter <code>group</code> denotes the name of a group. When this group is started, the counter gets reset to
* null.
*
* @author Thomas Morgner
*/
public class ItemAvgFunction extends AbstractFunction implements FieldAggregationFunction
{
private static final Log logger = LogFactory.getLog(ItemAvgFunction.class);
/**
* Useful constant for one.
*/
private static final BigDecimal ONE = new BigDecimal(1.0);
/**
* The item sum.
*/
private Sequence<BigDecimal> sum;
/**
* The item count.
*/
private Sequence<BigDecimal> itemCount;
private transient int lastGroupSequenceNumber;
/**
* The name of the group on which to reset the count. This can be set to null to compute the average for the whole
* report.
*/
private String group;
/**
* The name of the field from where to read the values.
*/
private String field;
/**
* The scale-property defines the precession of the divide-operation.
*/
private int scale;
/**
* The rounding-property defines the precession of the divide-operation.
*/
private int roundingMode;
private String crosstabFilterGroup;
/**
* Constructs an unnamed function. Make sure to set a Name or function initialisation will fail.
*/
public ItemAvgFunction()
{
sum = new Sequence<BigDecimal>();
itemCount = new Sequence<BigDecimal>();
scale = 14;
roundingMode = BigDecimal.ROUND_HALF_UP;
}
/**
* Constructs a named function. <P> The field must be defined before using the function.
*
* @param name The function name.
*/
public ItemAvgFunction(final String name)
{
this();
setName(name);
}
/**
* Receives notification that a new report is about to start. <P> Does nothing.
*
* @param event Information about the event.
*/
public void reportInitialized(final ReportEvent event)
{
clear();
}
private void clear()
{
this.sum.clear();
this.itemCount.clear();
this.lastGroupSequenceNumber = 0;
}
/**
* Receives notification that a new group is about to start. If this is the group defined for the function, then the
* running total is reset to zero.
*
* @param event Information about the event.
*/
public void groupStarted(final ReportEvent event)
{
if (FunctionUtilities.isDefinedGroup(getGroup(), event))
{
clear();
}
if (FunctionUtilities.isDefinedGroup(getCrosstabFilterGroup(), event))
{
final int groupIndex = event.getState().getCurrentGroupIndex();
this.lastGroupSequenceNumber = (int) event.getState().getCrosstabColumnSequenceCounter(groupIndex);
}
}
/**
* Returns the group name.
*
* @return The group name.
*/
public String getGroup()
{
return group;
}
/**
* Sets the group name. <P> If a group is defined, the functions value is reset to zero at the start of every instance
* of this group.
*
* @param name The group name (null permitted).
*/
public void setGroup(final String name)
{
this.group = name;
}
/**
* Returns the field used by the function. The field name corresponds to a column name in the report's data-row.
*
* @return The field name.
*/
public String getField()
{
return field;
}
/**
* Sets the field name for the function. The field name corresponds to a column name in the report's data-row.
*
* @param field the field name.
*/
public void setField(final String field)
{
this.field = field;
}
/**
* Returns the defined rounding mode. This influences the precision of the divide-operation.
*
* @return the rounding mode.
* @see java.math.BigDecimal#divide(java.math.BigDecimal, int)
*/
public int getRoundingMode()
{
return roundingMode;
}
/**
* Defines the rounding mode. This influences the precision of the divide-operation.
*
* @param roundingMode the rounding mode.
* @see java.math.BigDecimal#divide(java.math.BigDecimal, int)
*/
public void setRoundingMode(final int roundingMode)
{
this.roundingMode = roundingMode;
}
/**
* Returns the scale for the divide-operation. The scale influences the precision of the division.
*
* @return the scale.
*/
public int getScale()
{
return scale;
}
/**
* Defines the scale for the divide-operation. The scale influences the precision of the division.
*
* @param scale the scale.
*/
public void setScale(final int scale)
{
this.scale = scale;
}
/**
* Receives notification that a row of data is being processed.
*
* @param event Information about the event.
*/
public void itemsAdvanced(final ReportEvent event)
{
final Object fieldValue = event.getDataRow().get(getField());
if (fieldValue instanceof Number == false)
{
return;
}
try
{
final Number n = (Number) fieldValue;
final BigDecimal number = ExpressionUtilities.convertToBigDecimal(n);
final BigDecimal oldSum = sum.get(lastGroupSequenceNumber);
if (oldSum == null)
{
sum.set(lastGroupSequenceNumber, number);
}
else
{
sum.set(lastGroupSequenceNumber, oldSum.add(number));
}
final BigDecimal oldValue = itemCount.get(lastGroupSequenceNumber);
if (oldValue == null)
{
itemCount.set(lastGroupSequenceNumber, ONE);
}
else
{
itemCount.set(lastGroupSequenceNumber, oldValue.add(ONE));
}
}
catch (final Exception e)
{
ItemAvgFunction.logger.error("ItemAvgFunction.advanceItems(): problem adding number.");
}
}
public void summaryRowSelection(final ReportEvent event)
{
if (FunctionUtilities.isDefinedGroup(getCrosstabFilterGroup(), event))
{
final int groupIndex = event.getState().getCurrentGroupIndex();
this.lastGroupSequenceNumber = (int) event.getState().getCrosstabColumnSequenceCounter(groupIndex);
}
}
/**
* Returns the function value, in this case the average of all values of a specific column in the report's
* TableModel.
*
* @return The function value.
*/
public Object getValue()
{
final BigDecimal count = itemCount.get(lastGroupSequenceNumber);
if (count == null)
{
return null;
}
final BigDecimal sum = this.sum.get(lastGroupSequenceNumber);
if (sum == null)
{
return null;
}
if (count.longValue() == 0)
{
return null;
}
return sum.divide(count, scale, roundingMode);
}
/**
* Return a completly separated copy of this function. The copy does no longer share any changeable objects with the
* original function.
*
* @return a copy of this function.
*/
public Expression getInstance()
{
final ItemAvgFunction function = (ItemAvgFunction) super.getInstance();
function.sum = function.sum.clone();
function.itemCount = function.itemCount.clone();
function.lastGroupSequenceNumber = 0;
return function;
}
public Object clone()
{
try
{
final ItemAvgFunction clone = (ItemAvgFunction) super.clone();
clone.sum = clone.sum.clone();
clone.itemCount = clone.itemCount.clone();
return clone;
}
catch (CloneNotSupportedException e)
{
throw new IllegalStateException();
}
}
public String getCrosstabFilterGroup()
{
return crosstabFilterGroup;
}
public void setCrosstabFilterGroup(final String crosstabFilterGroup)
{
this.crosstabFilterGroup = crosstabFilterGroup;
}
}